1. Field of the Invention
The present invention relates to tube restoring apparatus and method for restoring a flexible tube used for a liquid transfusing system or a blood transfusing system, or the like, and more particularly to tube restoring apparatus and method for restoring a deformed joint portion of flexible tubes of which inner surface is fused or stuck by fusion, to ensure fluid communication within the connected tube.
2. Description of the Prior Art
Conventionally, as tubes for connecting bags of a liquid transfusing system or a blood transfusing system, polyvinyl chloride tubes are mainly used. Since the polyvinyl chloride tube is formed of a thermoplastic resin, there has been developed sterile tube connecting device (SCD) and connecting method by the device which can connect cut-off tubes under the sterilized condition by utilization of the thermoplastic characteristics of the tubes (which are disclosed in for example U.S. Pat. No. 4,369,779). With this result, it has become possible to cut off and further connect tubes used in a system in which a plurality of bags are connected through the tubes, under the sterilized condition.
The above-mentioned sterile tube connecting device is composed of a cutting blade heated to such a temperature that the tube material can be melted, and two holding members for holding two tubes to be connected. For connection of the tubes, two tubes which are held horizontally and parallel with each other by the two holding members are cut off simultaneously with the heated blade. Further, under the condition that the cut-off surfaces of the tubes are in contact with the heated blade, the holding members are moved so that the cut-off surfaces of the two tubes can be brought into contact with each other, and then the blade is pulled out. However, when the blade is pulled out from between the two cut-off tubes, the cross-sectional shape of the connected tube is usually deformed, so that the tube (polyvinyl chloride) is hardened in the state where the cross-sectional shape of the tube is crushed. In other words, the cross-sectional shape of the tube is usually crushed at the respective joint portion, since the inner surface of the tube at the joint portion is fused or stuck by fusion, so that there is possibility that the tube is closed at the joint portion.
When the tube is crushed at the joint portion thereof after the tubes have been connected to each other, liquid or blood cannot flow therethrough. Therefore, in such a case, it becomes necessary to restore the shape of the deformed joint portion by applying external force to the stuck portion (fused portion) from the outside so as to tear or separate the fused portion formed inside the tube.
Conventionally, the above-mentioned tube restoring operation has been performed by manual operation after the two tubes have been connected to each other. Namely, the joint portion of the tube including the fused portion therein is pinched between the thumb and the index finger of the operator and then rolled therebetween, to separate or tear the fused portion of the tube.
However, since the connected tube is still heated immediately after the two tubes have been connected, there is a danger that the operator may be burnt. In other words, as far as the connected tube is to be restored in shape manually, it is necessary to wait for a certain time until the connected tube is cooled. Therefore, the tube restoring operation cannot be performed immediately after the tube connection process is taken place, thus leading to a problem in that the tube connection process cannot be so far automatized.